The SEDRIS Data Representation Model
APPENDIX B - Constraints
Face Ring Edge Consistency

Definition

The following constraints apply:

  1. For a <Feature Face Ring> instance R that associates to <Feature Edge> instances E1, ..., En, the following conditions shall hold:

    1. If n = 1, E1 shall be a loop such that its start and end <Feature Node> instances are the same <Feature Node> instance.

    2. If n > 1, for each Ei, Ei+1, where i = 1, ..., n-1, Ei and Ei+1 shall associate to a common <Feature Node> instance, and where i = n, E1 and En shall associate to a common <Feature Node> instance. For each consecutive <Feature Edge> instance within R, the <Edge Direction> link object shall be consistent with the starting and ending nodes of the edge.

    3. If n > 1, for each Ei, Ei+1, where i = 1, ..., n, there shall be at most one Ej, where j ≠ 1, such that Ej is the same <Feature Edge> instance as Ei but where the <Edge Direction> link objects for Ei and Ej have different forwards field values. If such an Ej exists, then, for every Ei, there shall be such an Ej.

  2. For a <Geometry Face> instance F that associates to <Geometry Edge> instances E1, ..., En, the following conditions shall hold:

    1. For each Ei, Ei+1, where i = 1, ..., n-1, Ei and Ei+1 shall associate to a common <Geometry Node> instance, and where i = n, E1 and En shall associate to a common <Geometry Node> instance. For each consecutive <Geometry Edge> instance within F, the <Edge Direction> link object shall be consistent with the starting and ending nodes of the edge.

    2. A <Geometry Edge> instance shall appear no more than once in F with any orientation.

Rationale

Replicated information shall be consistent.

Example

No example supplied.

FAQs

No FAQs supplied.


Prev: Face Direction Levels 0 3. Next: Faces Bordering Volumes. Up:Index.